The first of these philosophers was endowed with a lively and brilliant imagination, and clothed with the charms of a seducing language, the purest morals in paganism. In lending to the grave teachings of Socrates, the graces and liveliness of Lis spirit, Plato secured for them immense popularity, and an eternal duration, which they would not, perhaps, have obtained without these foreign ornaments. But we have not to consider here, either the profound moralist or elegant writer, worthy of the surname of the Swan of the Academy ; we can only occupy ourselves with Plato in his
character of physician, and especially in that of physiologist.
Let us see, in the first place, what mode of acquisition he employed in the study of the physical sciences. We shall let him speak for himself. " Very well," he says, in the Phaedon, " is anything more rational than to think by the thoughts alone, disengaged from all foreign or sensible agency ; to apply at once the pure essence of thought in itself, to the research of the pure essence of each thing in itself, without the ministry of the eyes and ears, without, in short, any intervention of the body, whose slightest influence only troubles the soul, and prevents it finding wisdom and truth. If we are ever to attain the knowledge of the essence of things, must it not be in this manner ? (Oeuvres completes de Platon, translated by M. Cousin, page 203)
It is clear, from what we have just quoted, that Plato undertook the study of the physical diseases, not by method of observation and experiment, but by that of pure meditation - by mental intuition. The following passage proves that he applied that method, not only to metaphysics and morals, but also to physics and physiology: " During my youth," he continues, " 1 had an intense desire to learn that science which is termed physics. I felt that it would be sublime to know the cause of each thing ; what created, destroyed, and sustained it in existence. I was tormented, in a thousand ways, by my efforts to learn whether it is the cold and hot elements in a state of corruption, as some pretend, which form animated beings ; if it is the blood, or air, or fire that causes us to think, or whether it is either of these, or the brain alone, that produces in us all our sensations, sight, hearing, and smell, which, in their turn, produce memory and imagination ; which, by reflection create science. I reflected, also, on the decomposition of all these things, of the changes which take place in the heavens and the earth, and at last would find myself confused and wholly disqualified for such researches."(lbid., p. 273)
The meditations of our philosopher having resulted in no positive knowledge touching the questions that he was anxious to understand, he did not deduce therefrom the very natural consequence, that it was possible that he might have followed a false course, and that the method which conducts most certainly to the discovery of abstract truths, such as the axioms of metaphysics, and morals, was not as sure to attain the knowledge of material things, of the truth of observation.(This is not the place to examine if the same mode of acquisition is applicable to all branches of human knowledge, as many ancient and modern philosophers have thought. This important question will become more proper in another chapter, where we shall treat it with all the consideration it merits) Plato never suspected the excellence of his method, and he was never tempted to try any other ; thus despairing, he returns to the origin of things, to explain in what their essence consists, when, having heard read in a book of Anaxagoras, the following proposition : mind is the regulator and principle of all things - " this idea," he says, "struck me like a stream of light."
Nothing more was necessary to inflame the imagination of the philosopher of the Academy, and create in his brain an entirely new system of physics. See how he reasons : " Since the intelligence is the first cause of all things, it must have ordered all things for the best possible end ; then, if any one desires to find the cause of everything, how it originates, perishes, or exists, he has only to ascertain to what end such thing is destined. Therefore," he adds, " I comprehend no longer, all the other learned causes that are offered us, but if any one comes to tell me what it is that makes a thing beautiful, or gives it liveliness of colors, or forms, or other similar things, I leave aside all these reasons, which only perplex me, and 1 assume, myself, without plan or art, and probably too simply, that nothing gives beauty but the presence or communication of the original beauty, in whatever way this communication may take place on this subject. I affirm nothing, except that all things beautiful are beautiful by the presence of beauty. "(Oeuvres Completes de Platon, page 283)
The reason which Plato has given for the beauty of things, naturally recalls that famous response of the schools of the Middle Ages, to the question, Why does opium produce sleep? Because it possesses the sleepy principle. But the passage we have just quoted, merits the attention of the reader for more serious reasons ; for it shows how and why the consideration of final causes was introduced into the natural sciences ; a consideration that has played an important part in more than one system of physics and physiology - one of the most unfortunate results of which has been to divert the human mind from the path of observation and experiment, and lull it into a species of quietism, extremely contrary to the progress of light.
But without anticipating the results that the Platonic method was destined to produce - results which we shall hereafter see develop themselves - let us be content, for the moment, with examining the benefit that Plato himself realized from it. in regard to the explanation of natural phenomena. As all parts of his philosophy are intimately connected, as is the case in that of Pythagoras, I shall be compelled to say something of his cosmogony before exposing his physio-pathological ideas : and if I am not always able to shed upon these abstract matters the clearness I would desire, I pray the reader to remember that the subtle Aristotle himself, the assiduous auditor of Plato, sometimes found the conceptions of his master too difficult to follow. It is in the dialogue entitled Timaeus, that the founder of the Academic sect has deposited the products of his meditations touching the nature of created beings in general, and of man in particular ; and it is from it that we extract the following summary.
Plato, like Pythagoras, maintained the idea, that God and matter existed from all eternity ; but that matter in itself had no form, property, or force. God gave it, from the beginning, a triangular form ; afterward, taking a certain number of primitive triangles, he composed the four primary elements, which we, in this lower world, term fire, air, earth, and water. Fire, which is the most subtle, is made up of the smallest number of triangles ; it has the figure of a pyramid. The air represents a solid of twelve faces, a dodecahedron. Water has the form of an icosahedron, or a solid of twenty faces. Finally, the earth, the heaviest of all the elements, constitutes a hexahedron, that is to say, a perfect cube, composed of right-angled triangles.
Thus, Plato, having borrowed from the philosopher of Samos the dogma of the homogeneity of matter, went yet farther than he in the field of hypothesis, for he attempts even to determine the primitive figure that the Creator must have given to atmospheric matter. He pretends that this figure is a triangle, because, of all the surfaces, the triangular is the most simple, and there is no geometrical figure which may not be divided into triangles.
While matter remains in its elementary state, it does not affect our senses in any way. For matter to become perceptible, it is necessary that several elements unite, and form an aggregate. Thus all the material substances which we know, and to which we assign particular names, result from the assemblage of various elements. Water, for example, which we see, feel, and employ in so many various ways, is not elementary water. The liquid body which we call water is, according to Plato, a compound, in which the aqueous element enters in a much larger proportion than the other elements.
This philosopher also admits, with Pythagoras, the existence of different orders of created spirits. He says, that the Supreme Intelligence charged the secondary gods with the formation of mortal animals. These gods, having received from the hands of the Celestial Father the immaterial principle of the human soul, fashioned a body for it with the most regular and polished of the primitive triangles. This luminous and incorruptible body, which envelopes the immaterial soul, was placed in the brain of man. The gods endowed, also, the visible and grosser body of the animal with another, mortal soul, the seat of the violent and fatal passions. This occupied the length of the spinal marrow, leaving between it and the divine soul, the interval of the neck, for fear that the two substances, of a nature so different, being too closely connected, the least pure might tarnish or embarrass the other by its contact.
" Therefore," says the same author, " the gods placed the mortal soul in the chest and the trunk ; and as this soul contains a good and bad principle, they divided the cavity of the trunk into two departments, just as is done with the apartments of males from females, by means of the diaphragm, placed in the middle as a partition. Nearer the head, between the diaphragm and the neck, they placed the manly and courageous, or bellicose principle of the soul ; so that being submitted to, and in concert with the reason, it may restrain the revolts of the passions and desires, when these are unwilling to be controlled by the influences which reason sends down from its citadel.
" That portion of the soul which requires food and drink, and all that the nature of our body renders necessary, is located between the diaphragm and the umbilicus. The gods have extended it over this entire region, like a rack, where the body may find its food. They have confined it there, like a ferocious beast, which it is necessary, nevertheless to feed, so that the mortal race may subsist.
" The authors of the human species having foreseen that we would be intemperate in eating and drinking, and that by gormandizing we should exceed very much the limits of what is proper and necessary ; therefore, in order to prevent us from destroying ourselves at once by diseases, and for fear that the race would thus soon become extinct, they arranged what is termed the lower bowels, to serve as a receptacle for the superfluous food and drinks, and they surrounded it with the folds of our intestines, for fear that the aliment, by passing too rapidly through the body, would create, too soon, the necessity for its renewal, which in making us insatiable gourmands would divert us from the cultivation of philosophy, and the muses, and from the obedience we owe to that which is Divine, within us."
Plato enumerates this way the principal parts of the body, and supposes that he had sufficiently explained the manner in which each one was generated, when he announced its functions ; or, to use his own expression, when he enumerated their final causes. But I think I have shown enough to convince the reader of the emptiness and nothingness of this kind of explanations, in the physical sciences.
As to the physiology of the same author, it is extremely succinct, and limited to some generalities. It emits no new idea, no principle, which has not been explicitly developed in the Hippocratic works, with the exception of the idea of elementary triangles, that Plato found means to bring in everywhere. " The nature of diseases," he says, " has something in common with that of animals. They are developed within a limited period, the same as each species ; each animal is born to live for a certain determined period, barring the accidents that may occur ; for the triangles which constitute each animal are disposed to last for a certain length of time, beyond which the animal can not survive. It is the same with diseases ; but if they are disturbed before a fixed time, by the employment of remedies, the smallest grow larger, and a single one attracts many. It is better to treat them by regimen, as far as possible, and not disturb them by medicines. Let this suffice for the animal and his corporeal part."
In bringing out some of the physico-psychical naivete's of Plato, I am far from desiring to cast ridicule on the conceptions, sometimes bold, but always brilliant, of one of the most splendid geniuses of antiquity. 1 am aware that seen in the lights of his age, the fictions of this philosopher are not as eccentric as they appear to us at first sight, since they have been reproduced in many writings, in totality or in part, almost as far down as our times ; but I wish to show by a great example, in the first place, that the introduction of final causes into Physics and Medicine, has only been a source of deceptions ; next, that the purely speculative method, so exact and fruitful in mathematics, has only led to futile dreams, and the play of the imagination, the sublimest minds that have attempted, by this method, to seek the properties of matter, and the explanation of the phenomena of nature. This will be more and more apparent, as we advance in this history, and new examples, not less illustrious than the preceding, will come to confirm this. I will deduce, for the present, two practical results : first, that it requires above all things, to choose a good method by which to acquire and cultivate the sciences; second, that every system of physics, or of medicine, which does not repose on accessible facts, or the immediate appreciation of the senses, is, at least, very hazardous, for where the senses can not penetrate, imagination reigns as sovereign.
Philosophers point out two principal modes of acquisition : the one, which they name logical, or rational, consists in establishing, at the commencement, some general propositions, or abstract principles, whence they deduce, by reasoning, the solution of all particular causes : thus, in mathematics is deduced from the axiom, " two quantities equal to a third, are equal to each other," the solution of a multitude of problems. So, also, from the following moral principle, " do unto others, as you would have them do unto you," the casuist deduces a mass of special precepts. Plato, who knew no other method, is then, very excusable for having pretended to derive an entire system of cosmology and physiology, from that antique dogma : the Supreme Intelligence has ordered every thing for the best possible ends."
The other mode of acquisition, called the empirical, or experimental, consists in observing, first, a great number of particular cases or phenomena, comparing them with each other, and noting their similitude and differences ; finally, to express what they have in common, by general or abstract propositions, which constitute axioms. In this way, Hippocrates, having seen, time and again, patients who had many parts of their body affected, yet complained of one only, deduced from his observations, the following aphorism : "in two simultaneous pains, the more intense obscures the other ;" and so the natural philosophers, having observed that water rises in the body of a pump, in proportion as the piston is withdrawn, a little too hastily concluded that nature abhors a vacuum.
The first method, it is seen, proceeds from generals to particulars, from the abstract to the concrete, from the axiom to the phenomenon ; the second, on the contrary, advances from particulars to generals, from the concrete to the abstract, from the phenomenon to the axiom. Both methods have their advantages, their inconveniences, and their proper uses. Far from being opposed to each other, as has been pretended, these two methods fortify and enlighten each other, and the truth never takes hold of us in a more irresistible manner, than when it is attained by both routes at once. Certain ideologues have erroneously called the first method, the synthetic, and second, the analytic : the words synthesis and analysis, employed in this acceptation, make nonsense, as has been well remarked by a modern metaphysician, and as I shall demonstrate hereafter myself. (See end of the volume- the doctrine of Barthez on the Vital Principle)
From History of Medicine by P.V. Renouard M.D.